I have just uploaded the next update, version 0.48.03. This now adds support for the SN75160 and SN75161 GPIB transceiver chips. Two GPIO pins are required to drive the TE control pins on the transceivers and the DC pin on the SN75161, although this can be reduced to one by coupling direction control (DC) pin on the SN75161 to REN, which already provides the required state change between controller and device modes.
There is currently one known issue. With the SN75160 and SN75161 chips placed between the Arduino and the GPIB bus, the ++lon command seems to work a little erratically. The command still works, but seems to miss some characters. This will require further investigation.
With the SN75160 and SN75161 chips in place, an interface can now have the full 48mA current handling available and provide tri-state outputs so that the interface will not cause problems on the GPIB bus when the interface is powered down. I have only tested on a breadboard and with two Arduinos and a DMM, but using these transceiver chips might even allow STM32 "blue pill" boards to be used. Of course, some kind of daughterboard will need to be devised in order to make use of them, but I am sure that suitable shields can be designed for any supported MCU board. I might even have a go at designing one myself....